Tombstoning is a common and potentially serious manufacturing defect that occurs during the PCB reflow process. To prevent this defect, designers and manufacturers should focus on optimizing their stencil design, solder paste volume, thermal profiles, and component placement. By taking these steps, they can help to ensure that their PCBs are functioning correctly and efficiently, and that they are delivering the high-quality products that their customers demand.
Tombstoning can have serious consequences for the functionality of a PCB and can even cause complete failure of the entire device.
There are several factors that can contribute to tombstoning, including uneven heating, incorrect component placement, poor stencil design, and not applying enough solder paste.
It is important to ensure that components are placed accurately and consistently on the PCB during the Pick and Place process. This is achieved through the use of automated placement machines, which can help to minimize human error and ensure a speedy, accurate, and consistent placement.
Furthermore, PCB designers can take steps to minimize the risk of tombstoning by optimizing the board layout and selecting components that are less prone to this defect. Smaller passives like ‘0201’ and ‘0402’ tombstone much more often than larger components. Footprint size and dimensions matter a good deal when working with smaller components.
When designing for manufacturing, keeping these things in the back of your mind when you make decisions, is an easy way to lower QC failure fates.